b2therye's ski's

[b2therye]

I suppose an obligatory G'Day is in order...

Before start the build thread, I'd like to thank the entire Skibuilders.com forum for all the guidance, inspiration, successes and failures that you've all posted of which I have studied over the past few months in preparation to building my own set of skis.
Now as I go through my build let’s not point out where I've completely ignored the wise lessons shown on this forum, shall we?

I’ve started my design by looking at a range of skis available and trawling countless sources as to what design practices I should follow. As I started while looking at custom ski building companies and the old key of matching a person up to a certain sized ski I thought that the design of a ski would be linked to a person’s height and weight and for every person there would be a ‘sweet spot’ of the perfect ski; now I have come to realise like almost anything it is a compromise between factors (correct me if you feel like you disagree).

Take for instance Length; I believe it is a compromise between manoeuvrability and stability. And deciding all the differing variables depends on not the skiers height and weight but their ski style and preferences. My previous set of skis were a set of Dynastar 6th sense serials being 158cm with 110/80/103 profile and a 15m Radius. These are nice, I felt like it was lacking in top speed and when going fast I sometimes had a bit of hooking and death wobbles.

My new set is 170cm, 116/90/113.5 with an 18m Radius:



And with playing around with numbers I’ve got the rough shape of the Mould to give me a 132cm running length:



First I’ve sourced paulownia wood for the core:



Profiled to 2.5 → 12 → 2.5 (my girlfriends cousin has a furniture shop and has let me use it on the weekend)



We made a jig to cut out the mould, and we started cutting





Now on to the base, I’ve sourced NHS ‘race base’ from blankslateskis.com



Now for the edges (again from blankslateskis.com); btw if anyone knows how to get ski materials like edges, base and VDS in Australia please let me know.



As I’m going to vacuum mould these, the cores weren’t exactly easily fitting to the mould shape so we clamped them, wet them down and added some weight



And now I’m buggered.

On the next instalment: Layup time!

Stay tuned.

[gozaimaas]

Nice to see another sydney based builder!
Good luck with it all mate.

[gozaimaas]

Looking at your tip/tail moulds they are quite severe. I think you need to look at that as you will struggle to pull it down with full length core and vacuum.
IMO chop the cores and use tip fill or pre bend the cores beyond the actual shap of the mould.
Ive had voids in my layup due to the same problem using a pneumatic press and less aggressive angle changes in the mould.

[b2therye]

Love it how many Aussies build their own

Good tip, ill add some chocks under the middle and continue pre-bending.

[chrismp]

The bindings won't stay on these skis for long with just paulownia as a core. I suggest you use either snowboard inserts (which would be likely to push into the core as well if tightended too hard) or you add another denser species of wood at least under the binding screws. I've built quite a few snowboard with paulownia and I've always added beech stringers into the core where the binding inserts go.

[b2therye]

Man, I don't want to have to remake my core!

bugger....

[gozaimaas]

Ive got heaps of inserts if you need some. What I do if putting inserts into soft timber like paulownia is put down some light weigh fibreglass under the core and push the inserts through. This provides a hard seat for the insert to pull against and stops the inserts sinking into the core

[chrismp]

You could just cut out a section in the center and add inlays made of a denser wood. Wouldn't be too much of a hassle this way. Check out SleepingAwake's build journal to see how he did the inlays with his balsa cores: http://www.skibuilders.com/phpBB2/viewt ... c&start=30

[Richuk]

Can you put stops (5mm AL plates) at each end of you mould so that core can be pressed/clipped into place? It would stop any lateral core shift and help position the core if you use inserts.

Creating a jig for the inserts is do-able.

[b2therye]

I was planning on buying new bindings when I finished these so I don't have the binding measurements, thats why i didn't go for binding inserts.

Maybe i can get away with using these E Z Lok Thread inserts for Softwood



http://www.catalogds.com/db/service?dom ... sh_zinc_mc

they come in an M6 x 1.0

Ill test some weight on an offcut.

Otherwise ill have to go for chrismp's suggestion of adding in a hardwood in the binding area.

I think we have Chilean Myrtle at the workshop.

[Richuk]

Binding Freedom or Quiver Killers. Maybe the holes can be soaked in penetrating epoxy before final fitting. It would be worth running a test to see how strong the result is likely to be.

[cainguy]

Which bindings do you plan to use? Lots of templates here.

http://www.techinfo.bindingfreedom.com/ ... lates.html

[chrismp]

If you don't add a denser species of wood, at least beef up the binding area with more fiberglass and maybe some aramid and use quiver killer inserts.

[b2therye]

I was planning on using carbon/kevlar for above the core, how many layers you think?

[chrismp]

No idea as I don't build skis and it's not needed for snowboards as the inserts provide enough resistance against pulling out. However, I'm sure the bindings you could use all have their screw holes in more or less the same place, so you could just add hardwood inserts into your core that would fit any binding model you're contemplating.